Solute Mixing in the Surf Zone
Publication: Journal of Waterway, Port, Coastal, and Ocean Engineering
Volume 135, Issue 4
Abstract
An experimental study has been undertaken within the U.K. Coastal Research Facility (CRF), located at HR Wallingford Ltd. Detailed measurements were made to examine the on–off shore spreading of a solute, mostly inside the surf zone, for shore normal waves combined with a longshore current. The results show that the on–off shore mixing is significantly increased by almost 70 times, when compared to current-only conditions. A theoretical advection–dispersion mixing mechanism has been postulated. Using suitable estimates for the turbulent diffusion and on–off shore wave-induced velocity, a theoretical approximation to the overall mixing within the surf zone can be obtained. This theoretical analysis suggests that the on–off shore mixing in the surf zone is proportional to , where is the breaker wave height. It is demonstrated that within the surf zone, the on–off shore mixing is dominated by the effects of the on–off shore velocity. Some previous experimental studies to determine the magnitude of the mixing within the surf zone have been performed. However, the mechanisms responsible for generating the mixing were neither fully investigated nor reported. The previous studies, together with the results obtained from the CRF, are compared to estimates for the theoretical description of mixing developed within this present study. A good agreement exists.
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Acknowledgments
The writers gratefully acknowledge the UK Engineering and Physical Sciences Research Council (Grant Nos. GR/J/12499 and GR/T24081) for their financial support and the technical assistance of HR Wallingford for the research undertaken on the CRF.
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Published In
Journal of Waterway, Port, Coastal, and Ocean Engineering
Volume 135 • Issue 4 • July 2009
Pages: 127 - 134
Copyright
© 2009 ASCE.
History
Received: May 23, 2006
Accepted: Dec 10, 2008
Published online: Jun 15, 2009
Published in print: Jul 2009
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